In a semiconductor lasers using quantum well gain medium, a quantum well stack is mounted in an epi-down configuration. The stylus tube includes a tip integrally formed on one end thereof. The control unit, including a timer, is configured such that it receives the temperature signals from the temperature sensor and is able to establish an accumulated heat load value of the flash memory by integrating the resulting temperature values versus time. In either case, once the trigging system situation has returned to normal, the memory reverts to the normal operation. In the electro luminescent diode, an anode electrode is formed over the first and second regions.